XCIX. oggvorbis

The OGG/Vorbis file format, as defined by http://www.vorbis.com/
and http://www.vorbis.com/, is a scheme
for compressing audio streams by multiple factors with a minimum of
quality loss. This extension adds Ogg Vorbis support to PHP's
URL Wrappers. When used in read mode,
compressed OGG/Vorbis data is expanded to raw PCM audio in one of six PCM
encoding formats listed below.

Serial Number of stream within file. Must be unique within file.
Because of the potential to select a duplicate serial number within
a chained file, make efforts to manually assign unique numbers when
encoding.

Write only

Random

comments

Associative array of file comments.
Will be translated to strtoupper($name) . "=$value".
Note: This context option is not available in oggvorbis-0.1